Efficacy of electroacupuncture for myofascial pain in the upper trapezius muscle: a case series.

BACKGROUND Electroacupunture (EA) includes the passage of an electrical current through the acupuncture needle and is commonly used for pain relief. OBJECTIVE To evaluate the EA treatment effects for myofascial pain in the upper trapezius muscle. METHODS Twenty women aged ranging from 18 to 40 years (mean=24.95; SD=5.88 years), with a body mass index ranging from 19 to 25 kg/m2 (mean=22.33; SD=0.56 kg/m2), with regular menstrual cycles controlled by oral contraceptive, local or referred pain for more than six months and at least one myofascial trigger point in the upper trapezius participated in this study. The participants received a total of nine EA sessions over five weeks. The needles were inserted at the accupoints GB20, GB21, LV3, LI4, and at "ashi" points. A mixed current of 2 Hz and 100 Hz was applied alternatively every 5 seconds for 30 minutes. The outcomes were pain intensity measured by the visual analogue scale (VAS), pressure pain threshold (PPT) measured by an algometer, electromyography (EMG) and quality of life measured by the SF-36 questionnaire. Inter-occurrences between sessions were monitored. Paired t-test, Wilcoxon test, and repeated measure analysis of variance (ANOVA) having Tukey-Kramer as post-hoc tests were used. RESULTS Significant improvement in pain intensity and in PPT occurred after treatment (P<0.0001). EMG of the right trapezius during contraction increased significantly, suggesting muscle function enhancement; the quality of life improved, related to physical components of the SF-36 (P<0.05). CONCLUSION The EA showed to be a reliable method for myofascial pain relief. Large randomized blinded controlled trials might be carried out to confirm these results. Article registered in the Registro Brasileiro de Ensaios Clínicos under number RBR-4hb6f6.